NASA considers anti-matter spacecraft...

I consider that a bad Idea I mean we are talking about an ill funded agency that can't make a shuttle that does'nt have tiles that fall off. Do we really want then messing around with Antimatter ? And where would we find the Di-lithium anyway?

Post # 4 was, of course, supposed to be post # 1, but the black hole that ate the database produced a strange time distortion whereby the thread was created a couple of days ago, but the actual message that constituted the start of the thread only turned up today.

Anyway, if you read the article you'll see that an anti-matter drive is being considered as a much safer alterntive to launching a nuclear powered craft from within the atmosphere. Personally I think we should just build a good-sized particle accelerator at the Moon colony and do all this crap up there, but that's just me.

Considering that, despite long experience and broad use in industry, nobody has yet suceeded in bottling electrons, I doubt that any scheme involving bottled positrons [which vanish when they come in contact with normal matter] will meet with much success.

Of course, the dangers associated with "conventional" nuclear reactors and fission-thermal rockets are wildly exaggerated, both in the popular Press and by those who ought to know better. A beautiful concept which will surely [should!] not be implemented within a planetary atmosphere involves uranium or plutonium salts dissolved in water, which produce a jet of immensely superheated steam ; this avoids the thermal constraints inherent in approaches using fixed [generally solid] fuel elements, but of course releases radioactives to the environment, which a properly functioning NERVA-style plant will not. In this vein one need do no more than mention Project Orion, the reductio ad absurdum of rocketry in general.
In any case the quantity of radioactives, and the potential for dispersal, are infinitesimal compared to what coal-fired power plants dump into the air annually. A nuclear-fission thermal rocket is really not unsuitable, in itself, even for ground launch, although significant engineering problems with thrust-to-weight ratio remain unsolved [due generally to a lack of research effort, as with the fast-breeder].

Spaceshuttles, antimatter, gamma-rays ..... This whole project is only one "loose cannon" last-minute crew addition short of becoming a terrible disaster, and a really cool Bruckheimer movie.

"Did you know that more people are murdered at 92 degrees Fahrenheit than any other temperature? I read an article once. Lower temperatures, people are easy-going, over 92 and it's too hot to move, but just 92, people get irritable."